Question: $ { {-5} \times \left[\begin{array}{rr}{1} & {1} \\ {3} & {3}\end{array}\right] = {?} } $
Solution: To multiply a matrix by a number, multiply each item of the matrix by the number. ${\left[\begin{array}{rr}{-5}\times{1} & {-5}\times{1} \\ {-5}\times{3} & {-5}\times{3}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{-5} & {-5} \\ {-15} & {-15}\end{array}\right]}$